The ongoing development of communication circuits and channels for the synchronous transport module (STM), the 10 Gigabit Ethernet (IEEE 802.3ae) and several other applications require the use of pseudorandom bit sequence (PRBS) generators and PRBS checkers to test communication circuits and/or channels.
There are two major types of conventional PRBS checkers. The first type of PRBS checker requires a synchronizing circuit. Various implementations of this type of checker are disclosed in U.S. Pat. Nos. 3,648,237, 5,283,831, 4,771,463, 5,321,754, 3,694,757, 4,639,548 and 5,392,289, the disclosures of which are incorporated by reference herein.
The second type of PRBS checker uses a self-synchronizing technique. This technique is disclosed in U.K. Patent No. 1,281,390 to R. Westcott entitled “Testing Digital Data Transmission Systems,” 1972; and in “A 10-Gb/s Silicon Bipolar IC for PRBS Testing,” IEEE Journal of Solid State Circuits, vol. 33, no. 1, January 1998, the disclosures of which are incorporated by reference herein.